Energy Generating Electronic Skin With Intrinsic Tactile Sensing Without Touch Sensors

Abstract

Electronic skin (eSkin) with various types of sensors over large conformable substrates has received considerable interest in robotics. The continuous operation of large number of sensors and the readout electronics make it challenging to meet the energy requirements of eSkin. In this article, we present the first energy generating eSkin with intrinsic tactile sensing without any touch sensor. The eSkin comprises a distributed array of miniaturized solar cells and infrared light emitting diodes (IRLEDs) on soft elastomeric substrate. By innovatively reading the variations in the energy output of the solar cells and IRLEDs, the eSkin could sense multiple parameters (proximity, object location, edge detection, etc.). As a proof of concept, the eSkin has been attached to a 3-D-printed hand. With an energy surplus of 383.6 mW from the palm area alone, the eSkin could generate more than 100 W if present over the whole body (area ∼1.5 m 2 ). Further, with an industrial robot arm, the presented eSkin is shown to enable safe human−robot interaction. The novel paradigm presented in this article for the development of a flexible eSkin extends the application of solar cell from energy generation alone to simultaneously acting as touch sensors.Index Terms-Electronic skin (eSkin), energy harvesting, human−robot interaction (HRI), proximity sensing, solar cell, touch sensing. I. INTRODUCTIONElectronic skin or "eSkin" has recently emerged as a novel platform for advances in robotics, prosthesis, health diagnostics, therapeutics, and monitoring [1]. It allows robots and prosthetic limbs to gather tactile information from large area contacts and to exploit the same to operate in unstructured environment or to improve human−robot interaction (HRI) [2]-[6]. Likewise, eSkin has been explored for measurement of vital health parameters and to provide reliable, effective, and, sometimes, life-saving functions [7]-[9]. With increasing number and type of sensors (pressure, temperature, texture, proximity, etc.) and electronics associated with them on large area eSkin [10]-[13], a stable power supply is critical for practical usage [11], [14]. Thus, a realistic and accessible power source is urgently needed for a next-generation of smart, stand-alone, always-on eSkins. This is a challenge as the continuous power supply through batteries is not practical because they add weight, are not flexible, and may require redesigning of robotics platform [15], [16]. Likewise, for applications requiring intimate integration of eSkin

Energy Autonomous Sweat‐Based Wearable Systems

“…The ambient or the body's kinetic energy harvested with these methods is used for the powering of sensors and associated electronics. In some cases, these harvesters themselves also act as the sensors and are termed as “self‐powered.” [ 15,43,69,99 ] In context with sweat, the predominant study of sweat‐based energy generators relies on the operation of BFC, [ 77 ] a fuel cell that uses enzymes or microbial as catalysts to generate the power from bioelectrocatalytic reaction of common chemicals and metabolites (lactate, glucose, or alcohol) in sweat. These are discussed in detail in Section 3.…”

“…( Figure a). Adapting these technologies, a variety of wearable physical, chemical, bio, and optical sensor, [ 3,33,38–43 ] reported in recent years as self‐powered or energy‐autonomous, [ 15,33,44–47 ] can rely on energy generators, [ 21,33,48–51 ] electrochemical energy storage (EESs) devices, [ 3,26,31–35,44,52,53,55–57 ] wireless power technologies, [ 58–60 ] self‐powered sensors, [ 15,33,44–47 ] and hybrid energy system combining both energy generator and EES. [ 61 ] Several review articles have covered these technologies in detail, [ 47,62–68 ] in respective topics such as self‐powered biosensors, [ 69 ] self‐powered medical sensors, [ 70 ] enzyme‐based body‐worn devices, [ 71 ] and other technologies for the environment.…”

Multifunctional Electronic Skin With a Stack of Temperature and Pressure Sensor Arrays

“…HE electronic or tactile skin (e-Skin), composed of a variety of soft and flexible sensors, has been extensively investigated in recent years to bring the interactive artificial intelligent systems closer to mimicking the human skin [1][2][3]. For human skin-like functionality the e-Skin should allow to perceive and distinguish various spatiotemporal tactile stimuli such as pressure (static and dynamic), temperature, and strain etc [4,5].…”

“…This could enhance the granularity of the haptic information obtainable from e-Skin and could enable robots with human-like dexterity, cognitive skills, and abilities [4,[6][7][8]. The advantage of such e-Skin also expands to the provision of high-dimensional information from the environment for application in wearable health-monitoring system, smart phones, displays, and prosthetics [3,4,9,10].…”

3D printed packaging of photovoltaic cells for energy autonomous embedded sensors

“…To ensure that the sensing, actuating, and computing units on a robot are powered for a significant amount of time, these solutions have been complemented with the use various energy harvesting devices [13][14][15]. Among these, the photovoltaics emerge as most suitable due to the higher and enough energy they can generate to power various sensing/electronic components in robotics and other related applications [15][16][17][18][19][20][21]. Solar cells are also the optimum solution for prosthetics/robotics due to their low weight.…”